Diurnal appearance, fine structure, and chemical composition of fatty particles inHeterosigma akashiwo (Raphidophyceae)

PROTOPLASMA ◽  
1987 ◽  
Vol 137 (2-3) ◽  
pp. 134-139 ◽  
Author(s):  
M. Wada ◽  
Y. Hara ◽  
M. Kato ◽  
M. Yamada ◽  
T. Fujii
Keyword(s):  
Fine Structure ◽  
Chemical Composition

scholarly journals Submicroscopic Organization of Retinal Cones of the Rabbit

1958 ◽  
Vol 4 (6) ◽  
pp. 743-746 ◽  
Author(s):  
Eduardo De Robertis ◽  
Arnaldo Lasansky
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Chemical Composition ◽  
Outer Segment ◽  
Distal Portion ◽  
Cone Cell ◽  
Specific Chemical ◽  
General Plan ◽  
Clear Space ◽  
And Function

The fine structure of the cone cell of the rabbit is described and compared wtih that of the rod. The cone outer segment consists of a pile of flattened sacs with two membranes 30 A thick and a regular clear space in between of about 30 A. The membrane of the rod sacs is slightly thicker (∼40 A) and the clear space is less regular and frequently absent in the deeper regions. The distance between sacs is from 85 to 95 A in the cone and from 110 to 120 A in the rod, and the total repeating period is about 190 A and 210 A, respectively. These results are discussed in relation to the concentration of solids in both photoreceptors. A connecting cilium was observed in the cone cell and compared with that previously described in rods (4). This finding suggests that morphogenetically the cone may also result of the differentiation of a primitive cilium (5). The inner segment of the cone shows a distal portion with large concentration of elongated mitochondria and a proximal one with a large Golgi complex in the axis surrounded by components of the endoplasmic reticulum. It is concluded that both photoreceptors have a similar general plan of submicroscopic organization, with some minor difference in fine structure probably related to their specific chemical composition and function.

scholarly journals Cuticular Transpiration and Wax Structure and Composition of Leaves and Fruit of Vitis Vinifera

1967 ◽  
Vol 20 (6) ◽  
pp. 1149 ◽  
Author(s):  
JV Possingham ◽  
TC Chambers ◽  
F Radler ◽  
M Grncarevic
Keyword(s):  
Fine Structure ◽  
Chemical Composition ◽  
Vitis Vinifera ◽  
Light Petroleum ◽  
Replica Technique ◽  
Carbon Replica ◽  
Cuticular Transpiration ◽  
Leaf Wax ◽  
Surface Wax ◽  
Platelet Structure

The fine structure of the surface wax of leaves of sultana vines (Vitia viiUJera var. sultana) has been examined using the carbon replica technique. Leaf wax was found to be morphologically similar to the wax on the surface of grapes and to consist of a series of overlapping platelets. A brief period (30 sec) of exposure to light petroleum vapour disorganized the platelet structure of both leaf and fruit wax. This treatment markedly increased the cuticular transpiration of both fruits and leaves. The results are discussed in relation to the known chemical composition of these waxes. It is suggested that the surface wax, which consists of overlapping platelets that are hydrophobic in nature, may be important in controlling cuticular transpiration in both the fruit and leaves of grape.vines.

Chromoplasts in Rosa rugosa: Development and Chemical Characterization of Tubular Elements

1976 ◽  
Vol 31 (7-8) ◽  
pp. 456-460d ◽  
Author(s):  
Hans-Gunter Wuttke
Keyword(s):  
Fine Structure ◽  
Chemical Composition ◽  
Cross Section ◽  
Early Stage ◽  
Chemical Characterization ◽  
Longitudinal Axis ◽  
Rosa Rugosa ◽  
Polarizing Microscopy ◽  
Oriented Parallel

Abstract 1. Development and fine structure of the chromoplasts in hips of Rosa rugosa have been in­ vestigated by electron and polarizing microscopy. 2. The chromoplasts develop from chloroplasts. During disorganization of the thylakoid system characteristic strutures become visible: ‘oblique’ grana, U-shaped thylakoids, and occassionally ‘thylakoid teeth’ as well as thylakoid anastomoses. - In this early stage, tubules appear in the plastid matrix. They are sometimes connected with membranes, especially with thylakoids. 3. In ripe hips the chromoplasts are packed with tubules. These chromoplast tubules, which attain lengths of up to at least 1.5 μm, are non-ramified and lie parallel to each other. Their diameter is variable, with a mean of 18 nm. They are polygonal in cross-section with electron-dense walls and electron-transparent cores. Association of ellipsoidal osmiophilic globules with the tubules can often be seen. Irregularly swollen remnants of former thylakoids are found in connection with these tubules. In spindle-shaped chromoplasts, the tubules are oriented parallel to the longitudinal axis. Positive birefringence and positive dichroism are observed. 4. The chemical composition of tubule fractions has been analyzed. The tubules contain appreciable amounts of carotenoids, phospho- and glycolipids, and proteins. 5. The origin and development of the tubules is discussed. It appears likely that reorganization of part of the thylakoid system and synthesis of carotenoids are involved in the formation of tubules. 6. The plastids in the yellow autumn leaves of Rosa rugosa contain globules but not tubules.

scholarly journals Stellar parameters through high precision parallaxes

2007 ◽  
Vol 3 (S248) ◽  
pp. 500-501
Author(s):  
C. Jordi ◽  
C. Fabricius ◽  
J. M. Carrasco ◽  
F. Figueras ◽  
E. Masana ◽  
...  
Keyword(s):  
Fine Structure ◽  
Chemical Composition ◽  
High Precision ◽  
Spectrometric Data ◽  
Giant Step ◽  
Absolute Luminosity ◽  
Hr Diagram

AbstractBefore Hipparcos, the determination of absolute luminosity was usually done through calibrations based on a few stellar parallaxes measured at the highest precision. The Hipparcos mission meant a giant step on the knowledge of luminosities and fine structure of the HR diagram. The Gaia mission will go an enormous step further. Besides luminosities, Gaia will allow us to derive other stellar parameters like temperature and extinction, gravity, chemical composition, age and mass by the combination of astrometric and spectrometric data. Through simulations during the mission preparation, it has been shown that the astrometric parallax information is essential to deal with the degeneracy between gravity and chemical composition ([Fe/H] and [α/Fe]), that cannot be treated using only spectrophotometry. We show the expected HR diagram for the Gaia domain and the accuracies of stellar parameters.

scholarly journals The Submillimeter Wave Astronomy Satellite

1990 ◽  
Vol 123 ◽  
pp. 251-251 ◽  
Author(s):  
G.J. Melnick
Keyword(s):  
Fine Structure ◽  
Chemical Composition ◽  
Ground State ◽  
Molecular Clouds ◽  
Large Scale ◽  
Rotational Transition ◽  
Submillimeter Wave ◽  
Important Species ◽  
Structure Transition ◽  
Large Scale Survey

AbstractThe Submillimeter Wave Astronomy Satellite (SWAS) is a NASA Small-Explorer Class experiment whose objective is to study both the chemical composition and the thermal balance in dense (NH2 > 103 cm−3) molecular clouds and, by observing many clouds throughout our galaxy, relate these conditions to the processes of star formation. To conduct this study SWAS will be capable of carrying out both pointed and scanning observations simultaneously in the lines of four important species: (1) the H2O (110–101) 556.963 GHz ground-state ortho transition, (2) the O2 (3,3–1,2) 487.249 GHz transition, (3) the CI (3P1 – 3P0) 492.162 GHz ground-state fine structure transition, and (4) the 13CO (J = 5–4) 550.926 GHz rotational transition. These atoms and molecules are predicted to be among the most abundant within molecular clouds and, because they possess low-lying transitions with energy differences (ΔE/k) between 15 and 30K (temperatures typical of many molecular clouds), these species are believed to be dominant coolants of the gas as it collapses to form stars and planets. A large-scale survey in these lines is virtually impossible from any platform within the atmosphere due to telluric absorption.

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